My opinion is that masturbation and porn are too closely linked in the porn addict's brain to keep one and not have the other. A converse would be to ask if looking at porn without masturbating would help you quit masturbating. My guess is "no". Other examples (albeit imperfect) might be an alcoholic going to a bar to just have a soda, or a smoker wanting to stand outside with other smokers to smell the second hand smoke to help them satisfy their own cravings to help them quit. My own advice is to quit everything, and a softer version of that advice is to only consider taking up masturbation after you've had what you deem to be a successful reboot, where it is decoupled from porn. But, if you quit it and are okay with it out of your life, I am not sure why you'd want to invite it back into your life...? I'm not sure anyone on their deathbed is telling the people around them "I wish I'd masturbated more", but I digress.
Also, for many of those recovering, going a week without porn is pretty darn good. That's a sign of rewiring, albeit at a slower pace than if you were off entirely. Keeping relapses short makes the best use of it... when you have a once a week relapse, limit yourself to one "session", don't binge all afternoon and evening, and you'll find the mental health stuff to be less crushing. I know, easier said than done, the chaser effect can be big, but if you forgive yourself for the relapse and find something else to do for a while, you'll eventually find is easier than you think. It is slow, but you're slowly building up resistance to porn. I am going to guess that the once a week relapses have a trigger. For me it was on Sundays when loneliness and social anxiety were at their highest. Work days when I kept busy were fine, but Sundays were rough. Recognizing that a week is pretty darn good and looking forward to another porn free week ahead of you can help you avoid the "aw, f&*$ it" mentality that unfortunately comes with relapses. This is the downside to talking about "streaks", because it dismisses these small successes, and unnecessarily discourages real progress.
But don't take my word for it... pay attention to how you feel after masturbating. Not immediately after when the relaxation hits you, but afterward. Do you feel at peace or in a darker place?